package com.atguigu.gulimall.product.service.impl;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.TypeReference;
import com.atguigu.gulimall.product.service.CategoryBrandRelationService;
import com.atguigu.gulimall.product.vo.Catelog2Vo;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.cache.annotation.Caching;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;

import java.util.*;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;
import java.util.stream.Stream;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.atguigu.common.utils.PageUtils;
import com.atguigu.common.utils.Query;

import com.atguigu.gulimall.product.dao.CategoryDao;
import com.atguigu.gulimall.product.entity.CategoryEntity;
import com.atguigu.gulimall.product.service.CategoryService;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.util.StringUtils;


@Service("categoryService")
public class CategoryServiceImpl extends ServiceImpl<CategoryDao, CategoryEntity> implements CategoryService {

    @Autowired
    CategoryBrandRelationService categoryBrandRelationService;

    @Autowired
    StringRedisTemplate redisTemplate;

    @Autowired
    RedissonClient redissonClient;

    @Override
    public PageUtils queryPage(Map<String, Object> params) {
        IPage<CategoryEntity> page = this.page(
                new Query<CategoryEntity>().getPage(params),
                new QueryWrapper<CategoryEntity>()
        );

        return new PageUtils(page);
    }

    @Override
    public List<CategoryEntity> listWithTree() {
        List<CategoryEntity> entities = baseMapper.selectList(null);
        List<CategoryEntity> level1Menu = entities.stream().filter(categoryEntity ->
                categoryEntity.getParentCid() == 0
        ).map((menu) -> {
            menu.setChildren(getChildren(menu, entities));
            return menu;
        }).sorted((menu1, menu2) -> {
            return (menu1.getSort() == null ? 0 : menu1.getSort()) - (menu2.getSort() == null ? 0 : menu2.getSort());
        }).collect(Collectors.toList());
        return level1Menu;
    }

    @Override
    public void removeMenuByIds(List<Long> asList) {
        //TODO  1.检查当前删除的菜单，是否被别的地方引用

        //逻辑删除
        baseMapper.deleteBatchIds(asList);
    }

    //[2,25,225]
    @Override
    public Long[] findCatelogPath(Long catelogId) {
        List<Long> paths = new ArrayList<>();

        List<Long> parentPath = findParentPath(catelogId, paths);

        Collections.reverse(parentPath);

        return (Long[]) paths.toArray(new Long[parentPath.size()]);
    }

    /**
     * 级联更新所有关联的数据
     *
     * @param category
     */
//    @Caching(evict = {
//            @CacheEvict(value = "category",key = "'getLevel1Category'"),//调用这个方法的时候，删除getLevel1Category的缓存
//            @CacheEvict(value = "category",key = "'getCatalogJson'")
//    })
    @CacheEvict(value = "category",allEntries = true)
    @Transactional
    @Override
    public void updateCascade(CategoryEntity category) {
        this.updateById(category);
        categoryBrandRelationService.updateCategory(category.getCatId(), category.getName());
        System.out.println("调用了updateCascade方法");
        //同时修改缓存中的数据
        //redis.del("catalogJSON");等待下次主动查询进行更新
    }
    //每一个缓存的数据我们都来指定放到哪个名字的缓存【缓存的分区(按照业务类型分)】
    @Cacheable(value = "category",key = "#root.method.name") //代表当前方法的结果需要缓存，如果缓存中有，
    // 方法不用调用，如果缓存中没有，会调用方法，最后将方法的结果放入库存
    @Override
    public List<CategoryEntity> getLevel1Category() {
        System.out.println("getLevel1Category");
        List<CategoryEntity> entities = baseMapper.selectList(new QueryWrapper<CategoryEntity>().eq("parent_cid", 0));

        return entities;
    }

    /**
     * 1.空结果缓存:解决缓存穿透
     * 2.设置过期时间(加随机值): 解决缓存雪崩
     * 3.加锁:解决缓存击穿
     */

    @Cacheable(value = "category",key = "#root.methodName")
    @Override
    public Map<String,List<Catelog2Vo>> getCatalogJson(){
        System.out.println("查询了数据库getCatalogJson....");
        List<CategoryEntity> selectList = baseMapper.selectList(null);
        //1.查出所有一级分类
        List<CategoryEntity> level1categorys = getParent_cid(selectList, 0L);
        Map<String, List<Catelog2Vo>> parent_cid = level1categorys.stream().collect(Collectors.toMap(k -> {
            return k.getCatId().toString();
        }, v -> {
            //1.每一个一级分类，查到这个一级分类的二级分类
            List<CategoryEntity> categoryEntities = getParent_cid(selectList, v.getCatId());
            //2.封装上面的结果
            List<Catelog2Vo> catelog2Vos = null;
            if (categoryEntities != null) {
                catelog2Vos = categoryEntities.stream().map(l2 -> {
                    Catelog2Vo catelog2Vo = new Catelog2Vo(v.getCatId().toString(), null, l2.getCatId().toString(), l2.getName());
                    //1.找出当前二级分类的三级分类封装成vo
                    List<CategoryEntity> level3Catelog = getParent_cid(selectList, l2.getCatId());
                    if (level3Catelog != null) {
                        List<Catelog2Vo.Catelog3Vo> collect = level3Catelog.stream().map(l3 -> {
                            Catelog2Vo.Catelog3Vo catelog3Vo = new Catelog2Vo.Catelog3Vo(l2.getCatId().toString(), l3.getCatId().toString(), l3.getName());
                            return catelog3Vo;
                        }).collect(Collectors.toList());
                        catelog2Vo.setCatalog3List(collect);
                    }
                    return catelog2Vo;
                }).collect(Collectors.toList());
            }

            return catelog2Vos;
        }));


        return parent_cid;
    }


    public Map<String, List<Catelog2Vo>> getCatalogJson2() {
        //给缓存中放json字符串，拿出的json字符串，还要逆转为能用的对象类型；【序列化与反序列化】

        //1.加入缓存逻辑，缓存中存的数据是json字符串
        //JSON跨语言，跨平台兼容（PHP,JAVA等语言都可以兼容
        String catalogJSON = redisTemplate.opsForValue().get("catalogJSON");
        if (StringUtils.isEmpty(catalogJSON)) {
            //2.缓存中没有，查询数据库
            Map<String, List<Catelog2Vo>> catalogJsonFromDb = getCatalogJsonFromDbWithRedisLock();

            return catalogJsonFromDb;
        }
        //转为我们指定的对象。
        Map<String, List<Catelog2Vo>> result = JSON.parseObject(catalogJSON,
                new TypeReference<Map<String, List<Catelog2Vo>>>() {
                });
        return result;
    }

    /**
     * 缓存里面的数据如何和数据库保持一致
     * 缓存数据一致性
     * 1).双写模式
     * 2).失效模式
     * @return
     */
    public Map<String, List<Catelog2Vo>> getCatalogJsonFromDbWithRedissonLock() {
        //1.占分布式锁。去redis占坑
        RLock lock = redissonClient.getLock("CatalogJson-lock ");
        lock.lock();
        Map<String, List<Catelog2Vo>> dataFromDb;
        try {
            dataFromDb = getDataFromDb();
        } finally {
            lock.unlock();
        }
        return dataFromDb;
    }


    public Map<String, List<Catelog2Vo>> getCatalogJsonFromDbWithRedisLock() {
        //1.占分布式锁。去redis占坑
        String uuid = UUID.randomUUID().toString();
        Boolean lock = redisTemplate.opsForValue().setIfAbsent("lock",uuid,300,TimeUnit.SECONDS);
        if (lock){
            //加锁成功...执行业务
            //设置过期时间 以免代码执行期间(断电)出现问题 没来得及删除key 必须和加锁是同步的 原子的
            //redisTemplate.expire("lock",30,TimeUnit.SECONDS);
            Map<String, List<Catelog2Vo>> dataFromDb;
            try {
                dataFromDb = getDataFromDb();
            }finally {
                String script = "if redis.call('get', KEYS[1]) == ARGV[1] then return redis.call('del', KEYS[1]) else return 0 end";
                //删除锁
                Long lock1 = redisTemplate.execute(new DefaultRedisScript<Long>(script, Long.class),
                        Arrays.asList("lock"), uuid);
            }

            //redisTemplate.delete("lock");
            //获取值对比+对比成功删除=原子操作 lua脚本解锁
//            String lockValue = redisTemplate.opsForValue().get("lock");
//            if (uuid.equals(lockValue)){
//                //删除自己的锁
//                redisTemplate.delete("lock");
//            }

            return dataFromDb;
        }else {
            //加锁失败...重试。 synchronied()
            //休眠100ms
            try {
                Thread.sleep(200);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            return getCatalogJsonFromDbWithRedisLock();//自旋的方式
        }



    }

    private Map<String, List<Catelog2Vo>> getDataFromDb() {
        String catalogJSON = redisTemplate.opsForValue().get("catalogJSON");
        if (!StringUtils.isEmpty(catalogJSON)) {
            //缓存不为null,直接返回
            Map<String, List<Catelog2Vo>> result = JSON.parseObject(catalogJSON,
                    new TypeReference<Map<String, List<Catelog2Vo>>>() {
                    });
            return result;
        }
        /**
         * 1.将数据库的多次查询变为一次
         */
        List<CategoryEntity> selectList = baseMapper.selectList(null);


        //1.查出所有一级分类
        List<CategoryEntity> level1categorys = getParent_cid(selectList, 0L);
        Map<String, List<Catelog2Vo>> parent_cid = level1categorys.stream().collect(Collectors.toMap(k -> {
            return k.getCatId().toString();
        }, v -> {
            //1.每一个一级分类，查到这个一级分类的二级分类
            List<CategoryEntity> categoryEntities = getParent_cid(selectList, v.getCatId());
            //2.封装上面的结果
            List<Catelog2Vo> catelog2Vos = null;
            if (categoryEntities != null) {
                catelog2Vos = categoryEntities.stream().map(l2 -> {
                    Catelog2Vo catelog2Vo = new Catelog2Vo(v.getCatId().toString(), null, l2.getCatId().toString(), l2.getName());
                    //1.找出当前二级分类的三级分类封装成vo
                    List<CategoryEntity> level3Catelog = getParent_cid(selectList, l2.getCatId());
                    if (level3Catelog != null) {
                        List<Catelog2Vo.Catelog3Vo> collect = level3Catelog.stream().map(l3 -> {
                            Catelog2Vo.Catelog3Vo catelog3Vo = new Catelog2Vo.Catelog3Vo(l2.getCatId().toString(), l3.getCatId().toString(), l3.getName());
                            return catelog3Vo;
                        }).collect(Collectors.toList());
                        catelog2Vo.setCatalog3List(collect);
                    }
                    return catelog2Vo;
                }).collect(Collectors.toList());
            }

            return catelog2Vos;
        }));
        //3.查到的数据再放入缓存，将对象转为json放在缓存中
        String s = JSON.toJSONString(parent_cid);
        redisTemplate.opsForValue().set("catalogJSON", s, 1, TimeUnit.DAYS);

        return parent_cid;
    }

    //从数据库查询并封装分类数据
    public Map<String, List<Catelog2Vo>> getCatalogJsonFromDbWithLocalLock() {
        //只要是同一把锁 就能锁住需要这个锁的所有线程
        //1.synchronized(this) springBoot所有的组件在容器中都是单例的
        //TODO 本地锁：synchronized,JUC(Lock) 在分布式情况下，想要锁住所有，必须使用分布式锁
        synchronized (this) {
            //得到锁以后，我们应该再去缓存中确定一次，如果没有才需要继续查询
            return getDataFromDb();
        }
    }

    private List<CategoryEntity> getParent_cid(List<CategoryEntity> selectList, Long parent_cid) {
        //return baseMapper.selectList(new QueryWrapper<CategoryEntity>().eq("parent_cid", v.getCatId()));
        List<CategoryEntity> collect = selectList.stream().filter(item -> {
            return item.getParentCid() == parent_cid;
        }).collect(Collectors.toList());
        return collect;
    }

    private List<Long> findParentPath(Long catelogId, List<Long> paths) {
        //1.收集当前节点id
        paths.add(catelogId);
        CategoryEntity byId = this.getById(catelogId);
        if (byId.getParentCid() != 0) {
            findParentPath(byId.getParentCid(), paths);
        }
        return paths;
    }

    //递归查找所有菜单的子菜单
    private List<CategoryEntity> getChildren(CategoryEntity root, List<CategoryEntity> all) {
        List<CategoryEntity> children = all.stream().filter(categoryEntity -> {
            return categoryEntity.getParentCid().equals(root.getCatId());
        }).map(categoryEntity -> {
            //1.找到子菜单
            categoryEntity.setChildren(getChildren(categoryEntity, all));
            return categoryEntity;
        }).sorted((menu1, menu2) -> {
            //2.菜单的排序
            return (menu1.getSort() == null ? 0 : menu1.getSort()) - (menu2.getSort() == null ? 0 : menu2.getSort());
        }).collect(Collectors.toList());

        return children;
    }

}